Same formula different result

Hi all

I've 2 tables linked and as you can see in picture, the same formula give me 2 results:
- for the last (Tot.Imp.Commiss.) the result is ok (table "Provvigioni")

- for the first (Totale Quantità + Totale Imp.Fatt.) the result is the entire contents of the table

for the first 2 elements, I try with 2 formulas but result is the same.
Where I'm mistaken? Can somebody explain the logic?